Time to put all that turbo-power
to the ground!
Applications for all 135i & 335i models.

VAC Performance Rear Differentials are built to last with the
highest quality components, procedures, and technical expertise in
the industry. Our BMW differentials are run in countless race
series and by hundreds of street customers because our quality and
options are unmatched. Before we strictly built BMW's, we
have had an unmatched 50+ years of differential building expertise
in house!

This is a highly beneficial upgrade for not only tracked
cars, but street cars that drive in any weather!

Experts will tell you; proper differential assembly is one of the
most difficult things to tackle on an automobile. Take advantage of
our our precision and expertise as many happy customer and winning
teams have.
...Our differentials let your 335i and 135i really apply the torque
to where its needed:the ground!

Each of Our Performance differentials feature:

Expert assembly with the tightest standards for
tolerances and performance

OEM gaskets & seals

High grade hardware

Drastic performance increases by getting the power to the
ground

Improved overall drivability, and sense of safety by improving
stability in good as well as inclement weather

Increased acceleration via improved traction coming out of
corners and high torque situations

We offer:

Helical gear type TBDs from Quaife and Wavetrac

Clutch style LSDs from OS Giken

As the USA master distributor for Quaife
BMW, Stocking Dealer Of Wavetrac, and Master Dealer of OS
Giken- we have ALL the most popular solutions ready to quickly ship
to you...Check out our smoking deals on
completed Differential units: All diffs include all new Shims,
Seals, Crush Rings, Bolt kits and Gaskets:-

Price example ---Installing your Diff at VAC:Diff w/LSD installed (price in the table
above)
+Differential
Fluid (Wavetrac and
Quaife) +Shop materials &
Labor =
Total(We can
pre-build a diff for you when supplied with a core, and refund you
during installation)

-FAQs-

Q: I'm confused: I thought all I needed was a differential?
or LSD... What I am actually buying? What do I need?
-There are three parts of this upgrade that customers should
understand.
-First is the selection of the "carrier" or the actual mechanical
device that replaces the factory spider gears with a unit that puts
power to both wheels at once, rather than just the wheel with the
least traction. This is often referred to as the LSD (Limited Slip
Differential), but sometimes the entire housing once built is know
as the "LSD" so this can be confusing. This listing is for a
complete housing, ring and pinion, and LSD carrier.
-The second is the housing. The actual differential itself with the
ring and pinion gear, with the carrier unit installed is all
installed in side of the housing. That's the part you see under the
car with the gears and carrier inside.
-The third is the ring gear and pinion gear. These take the power
coming from the single drive shaft and split it horizontally so it
can go to both axles. When everything is professionally assembled,
your have our listing.

Q: Why does your 135 or 335 benefit so greatly from a
performance rear differential?:-Short Answer:
Improved acceleration, traction, and stability potential; as why
all M-Series are so equipped- AND why BMW left them out of all the
135/335/535 I, so they would not steal sales away from the
M-cars! -Long answer in simple terms:
Standard open-type differentials, equipped in most non-M Series
only send power to one wheel at a time in all conditions. The more
powerful a car becomes, the more traction is needed to effectively
make use of this power. "Traction control" is inefficient for
performance driving, and becomes more and more cumbersome as power
levels rise with tuning.
A 'Limited Slip Differential' or 'Torque Biasing Differential' is
able to effectively split power between both wheels at crucial
moments while keeping the car stable and easy to drive (Note: This
is by different means in different brands. LSD Vs TBD... OEM, Kaaz,
Quaife, Carbonetic, Wavetrac ect... see below).
When you launch your car from a stop, having the power continuously
sent to both wheels increases traction exponentially! You leave the
line with more power getting to the ground, and less power spinning
your wheels; this makes a car dramatically faster!
When your vehicle is turning, the outside wheel is rotating faster
than the inside wheel; the inside tire is doing less work. The
vehicle wants to 'lean' on the outside tire more, further
increasing it's load. While the outside wheel is forced to do more
work the inside has less traction- therefore, in an open
differential, the power wants to go to the wheel with the least
amount of resistance and it becomes wasted spinning the inside
wheel when cornering hard.
Through various means, a LSD or TBD effectively splits power to
both wheels and can aid in powering the car forward coming out of
turns as both wheels are utilized most effectively.
When entering a corner, this balance of traction helps to increase
the stability of the car when coming in at high speed improving
confidence and safety. This leads to faster corner entrance
potential.
All of this extra traction can also have improvements in low grip
conditions like snow or rain.

Application Info:

Q: What is in my car?

Model/
Transmission

Build
Date

Ring
Gear

Housing
Type

Gear Ratio

335i [Manual]

Aug, 06 - Feb, 07

Bolted

Large

3.08

Mar, 07

(Transition period) may be Bolted
or Welded

Large

3.08

Apr, 07- On

Welded

Large

3.08

335i [Automatic]

Aug, 06 - Aug, 07

Bolted

Large

3.46

Sep, 07- On

Bolted

Small (NO OS GIKEN)

3.46

------

335is [DCT]

All Production

Welded

Large

2.56

------

335d [Auto]

All Production

Welded

Large

2.81

135i / Manual

All Production

Welded

Large

3.08

135i / Auto

All Production

Bolted

Small (NO OS GIKEN)

3.46

135i / DCT

All Production

Welded

Large

2.56

Q: What does a torque biasing differential like Quaife or
Wavetrac do?
We have run a Quaife HARD in our daily driven and often tracked
cars with absolute success. Additionally we have installed dozens
of Quaife units in platforms other than E8x/E9x and they always
perform flawlessly. We have also installed and sold many Wavetrac
units, and can remark that they also perform well for slightly less
cost.
An ATBs (automatic torque biasing differential) job is to improved
acceleration, traction, and stability potential of the chassis.
Rather than using clutch plates as a method of operation, the
Quaife ATB uses sets of helical cut gear-pinions that run in
pockets, and mesh during normal driving. The Wavetrac, the
"Wavetrac device" a set of plates that migrate away from one
another when slippage of a wheel occurs.
Should one of the driven wheels begin spin however, these diffs
seamlessly and immediately start to generate a torque-bias thanks
to the axial and radial thrust of the helical gear pinions in their
pockets. Wavetrac is similar, but uses its "Wave" that they assert
allows for additional traction in '100% bias' (or zero traction)
situations such as when a wheel is lifted from the ground in a
corner.
The result is a progressive, smooth transfer of torque away from
the spinning side of the axle to the driven wheel, which is now
capable of transmitting a greater proportion of torque. Unlike a
clutch style LSD- the gear type units deliver performance without
the need for strip downs or rebuilds. There are no plates to wear
or break and these units retain standard vehicle gear oil without
special requirements (Wavtrac recommends gear oil without limited
slip additive).
All of this extra traction can also have improvements in low grip
conditions like snow or rain.
Quaife units are silent in operation, a Wavetrac unit may also be-
however some have a slight noise when entering first gear. They do
not need any electronics to be re-worked or traction control to be
effected in any way. Very cool and great for both street and track
use!

Why do you want a Quaife
ATB?
Improved acceleration, traction and stability. Rather than using
clutch plates as a method of operation, the Quaife ATB uses sets of
floating helical cut gear pinions that run in pockets and mesh
during normal driving. Should one of the driven wheels start to
spin however, the helical gears start to generate a torque bias
thanks to the axial and radial thrust of the helical gear pinions
in their pockets. The result is a progressive transfer of torque
away from the spinning side of the axle to the driven wheel, which
is now capable of transmitting a greater proportion of torque.
Unlike a plate style LSD the Quaife unit delivers performance
without the need for strip downs and rebuilds. There are no plates
or gears to wear or break and the ATB units retain standard vehicle
lubrication.

All QUAIFE differentials come with a life time warranty.

Maximizes traction and minimizes wheel spin

Proven in drag and circuit racing, rallying and road use

Maintenance free design and retains standard axle lubrication

Produced from British Steel billets throughout

CAD designed and CNC machined then inspected to ISO 9001
standards

Used by Ford, GM and Daimler-Chrysler as original equipment

Why do you want a
Wavetrac?
Improved acceleration, traction and stability. Rather than using
clutch plates as a method of operation, the Wavetrac- unlike other
helical units, have a patented 'Wavetrac Device'- a set of
complimentary surfaces that when one wheel has a total loss of
traction, the plates migrate away from each other allowing the
Wavtrac to continue to put power to the wheel with the most grip,
even in a situation where one wheel has a total loss of traction.
Other ATB units do not claim to be able to do this.
Unlike plate style LSDs, the Wavetrac unit delivers performance
without the need for strip downs and rebuilds. There are no
clutches or gears to wear or break and the ATB units retain
standard vehicle lubrication.

Maximizes traction and minimizes wheel spin

Maintenance free design and retains standard axle lubrication

Quiet and smooth
operation*

Much better acceleration
potential

*A slight sound may occur only when entering first-gear

What does a Clutch-type Limited Slip differential like an OS
Giken do?
Through clutch plates with internal mechanisms, a clutch type LSD
applies load to both rear wheels and aids in powering the car
forward when the wheels are turning at different rates, or when
acceleration off the line. As with powerful cars, taking advantage
off all the traction available from a standing start and in the
corners is important, however- clutch type LSDs for BMWs are setup
with some locking affect on deceleration as well: when entering a
corner, this load and balance of traction helps to increase the
stability of the car when coming in at high speed improving
confidence and safety. This leads to faster cornering potential.
This is what Japanese companies refer to as a 1.5 way LSD, and is
excellent for everything from daily drivers to all out competition
vehicles.
A 2-way LSD has a strong locking effect on deceleration- this is
typically utilized for those who like drifting as it can enhance
stability off throttle over-steer. These units are supplied by
special order.

Why do you want an OS Giken
LSD?
Improved acceleration, traction and stability. OS Giken
manufactures one of the worlds best Clutch-Type LSDs available.
Fully progressive with 100%
locking capability, no break-in, extremely long life and nearly
completely-silent. This is the ultimate way to put power to the
ground for those that have a more aggressive driving style, or who
are setting up a competitive car.
Not only do you get the advantages of acceleration, but the clutch
type LSDs are available with different locking profiles for
different driving styles. This makes them great for the high
speeds of road racing and track use.
OS Giken's Superlock is not just for racing, its also found its way
into BMW, Porsche and AMG street cars around the world for its
exceptional street mannerisms and quiet performance.
All of this extra traction can also have improvements in low grip
conditions like snow or rain. If you want a
the best unit OSG has to offer, that the Traction Control
Differential (TCD) adds special plates that circulate oil
constantly during use to make the most of of there technology:
super-silent and the cool running differential in there lineup.

Exceptionally long life

Maximizes traction and minimizes wheel spin

Excellent for drifting, road racing or street driving

Super quiet even though it uses clutch plates

Made in Japan

Used in many high-profile
championship wining vehicles of the past decade

Why VAC?
VAC Performance Rear Differentials are built to last with the
highest quality components, procedures, and technical expertise in
the industry. We have been building differentials since the 1950s,
and have been specializing in BMW since the1980s. With countless
2002s, E30s, E36, E46, E92, 7series, 5 series, street, race &
many custom projects... we have done it all. We have left no stone
unturned in 60 years in the machine shop business, so you can rest
assured that the job will be done right the first time.
Our results are the most proven: Our BMW differentials are run in
countless race series and by hundreds of street customers because
our quality and options are unmatched. All is performed in our
complete machine shop which ensures top qualify control. We do not
have to worry about subbing out work to another business who
may-or-may-not do the job properly.
Also importantly; there will be no back log. We are proud of our
process and we invite anyone to stop by the shop for a
tour.